#include <iostream>

void print_result(int lower, int higher, int sum)
{
	std::cout << "Sum from " << lower << " to "
		<< higher << " is " << sum << std::endl;
	
}
int main()
{
	int a, b;
	std::cin >> a >> b;
	int c = 0;
	int sum = 0;
	int at = a;
	while(at <= b)
	{
		c++;
		at++;
		sum += at;
	}

	if(c != 0)
	{
		print_result(a, b, sum);	
		return 0;
	}

	while(at >= b)
	{
		sum += at;
		at--;
	}
	print_result(b, a, sum);	
	
	return 0;
}
